Thanks for your inquiry. Not sure about the meaning of error factor for BMI055 accel and gyro.
In BMI055 datasheet we have specified typical offset change over temprature (TCO) parameters for accel and gyro respectively. For example, the typical accel TCO is +/-1mg/K and gyro +/-0.015dps/K. So when temperature changes from 25C to -10C for example, then the offset change for accel will be within the range of +/-1mg/K * (25C +10C) = +/-35mg, while gyro offset change within the range of +/-0.015dps/K * (25C + 10C) = +/-0.525dps (degree per second).